A wide variety of elements are used to treat fluids, i.e., gases, liquids, and mixtures of gases and liquids. Examples of fluid treatment elements include separation elements, such as filter elements and separator elements, coalescer elements, and mass transfer elements. They may be used in a wide variety of ways including to remove one or more substances, such as solids, liquids or chemical substances, e.g., a protein, from a gas or liquid; to concentrate or deplete one or more substances in a gas or liquid; to accrete one phase of a fluid, e.g., a liquid discontinuous phase, in another phase of the fluid, e.g., a continuous liquid or gas phase; or to transfer mass, such as a gaseous or chemical substance, between two fluid streams. In use, any of these elements may develop an electrical change imbalance or buildup that can potentially damage the fluid treatment system.
For example, filter elements, in addition to removing contaminants such as solids from fluids, may remove or add electrons to fluid passing through the filter elements, causing an imbalance in electrical charge or potential between the fluid, the filter element, and/or the surrounding housing, pipes, and fluid cavities. A gradual buildup of electrical charge may eventually lead to a discharge through a path of least resistance to, for example, the filter housing, the pipes, or any other conductive component such as a turbine-bearing cage. This discharge can degrade the fluid or harm the components experiencing a discharge arc. The service life of the fluid, the filter element, and the system containing the fluid is thus reduced.
Various techniques exist that purport to deal with the accumulation of charge and the resulting discharge in fluid treatment systems. One technique is to add conductive additives to the fluid. This technique can degrade fluid performance and also requires regular monitoring as the additive's effectiveness diminishes over time and use. Another technique is to provide some path to ground through the fluid treatment element. However, many of these grounding techniques require that extraneous and expensive components be included to provide a conductive path to ground. This not only increases the cost of the fluid treatment elements, it can also reduce the performance of the fluid treatment element, e.g., increase the pressure drop through the fluid treatment element. Further, these grounding technique often lead to complicated and expensive retrofitting of older systems to prevent the undesirable discharges.